Change the notification stream timeout used in tests.
Change the notification stream timeout used in tests.

The existing value of 10 seconds will cause any client test to fail that
takes that long without producing a notification.  This is probably a
cause of occasional transient test failures.  These would manifest as
failures at somewhat different points in tests, as the exact timing is
not consistent.

manthey/girder,Kitware/girder,Kitware/girder,girder/girder,RafaelPalomar/girder,jbeezley/girder,jbeezley/girder,Kitware/girder,Kitware/girder,girder/girder,RafaelPalomar/girder,RafaelPalomar/girder,RafaelPalomar/girder,RafaelPalomar/girder,jbeezley/girder,manthey/girder,manthey/girder,jbeezley/girder,girder/girder,girder/girder,manthey/girder